diff --git a/docs/libcurl/opts/CURLOPT_HSTSREADFUNCTION.3 b/docs/libcurl/opts/CURLOPT_HSTSREADFUNCTION.3
index 89c423c2e5..8d0b87d002 100644
--- a/docs/libcurl/opts/CURLOPT_HSTSREADFUNCTION.3
+++ b/docs/libcurl/opts/CURLOPT_HSTSREADFUNCTION.3
@@ -5,7 +5,7 @@
 .\" *                            | (__| |_| |  _ <| |___
 .\" *                             \___|\___/|_| \_\_____|
 .\" *
-.\" * Copyright (C) 1998 - 2021, Daniel Stenberg, <daniel@haxx.se>, et al.
+.\" * Copyright (C) 1998 - 2022, Daniel Stenberg, <daniel@haxx.se>, et al.
 .\" *
 .\" * This software is licensed as described in the file COPYING, which
 .\" * you should have received as part of this distribution. The terms
@@ -27,6 +27,13 @@ CURLOPT_HSTSREADFUNCTION \- read callback for HSTS hosts
 .nf
 #include <curl/curl.h>
 
+struct curl_hstsentry {
+  char *name;
+  size_t namelen;
+  unsigned int includeSubDomains:1;
+  char expire[18]; /* YYYYMMDD HH:MM:SS [null-terminated] */
+};
+
 CURLSTScode hstsread(CURL *easy, struct curl_hstsentry *sts, void *userp);
 
 CURLcode curl_easy_setopt(CURL *handle, CURLOPT_HSTSREADFUNCTION, hstsread);
diff --git a/docs/libcurl/opts/CURLOPT_HSTSWRITEFUNCTION.3 b/docs/libcurl/opts/CURLOPT_HSTSWRITEFUNCTION.3
index cee41d7b9c..edc56d308e 100644
--- a/docs/libcurl/opts/CURLOPT_HSTSWRITEFUNCTION.3
+++ b/docs/libcurl/opts/CURLOPT_HSTSWRITEFUNCTION.3
@@ -5,7 +5,7 @@
 .\" *                            | (__| |_| |  _ <| |___
 .\" *                             \___|\___/|_| \_\_____|
 .\" *
-.\" * Copyright (C) 1998 - 2021, Daniel Stenberg, <daniel@haxx.se>, et al.
+.\" * Copyright (C) 1998 - 2022, Daniel Stenberg, <daniel@haxx.se>, et al.
 .\" *
 .\" * This software is licensed as described in the file COPYING, which
 .\" * you should have received as part of this distribution. The terms
@@ -27,6 +27,18 @@ CURLOPT_HSTSWRITEFUNCTION \- write callback for HSTS hosts
 .nf
 #include <curl/curl.h>
 
+struct curl_hstsentry {
+  char *name;
+  size_t namelen;
+  unsigned int includeSubDomains:1;
+  char expire[18]; /* YYYYMMDD HH:MM:SS [null-terminated] */
+};
+
+struct curl_index {
+  size_t index; /* the provided entry's "index" or count */
+  size_t total; /* total number of entries to save */
+};
+
 CURLSTScode hstswrite(CURL *easy, struct curl_hstsentry *sts,
                       struct curl_index *count, void *userp);